Mass outflow rate from accretion discs around compact objects

Abstract

Abstract.We compute mass outflow rates from accretion disks around compact objects, such as neutron stars and black holes. These computations are done using combinations of exact transonic inflow and outflow solutions which may or may not form standing shock waves. Assuming that the bulk of the outflow is from the effective boundary layers of these objects, we find that the ratio of the outflow rate and inflow rate varies anywhere from a few percent to even close to a hundred percent (i.e., close to disk evacuation case) depending on the initial parameters of the disk, the degree of compression of matter near the centrifugal barrier, and the polytropic index of the flow. Our result, in general, matches with the outflow rates obtained through a fully time-dependent numerical simulation. In some region of the parameter space when the standing shock does not form, our results indicate that the disk may be evacuated and may produce quiescence states.

Mass Outflows from Dissipative Shocks in Hot Accretion Flows

“…Although continuous accreting solutions (i.e., shock-free solutions) are persistently present even for smaller energy E 1 (as expected), we do not find shocked flow solutions (or perhaps they are present but in much narrower parameter space). It can be speculated that maybe by prohibiting our jump condition in energy (energy dissipation at a shock front), we may obtain shock-driven outflows for smaller flow energy E 1 , which could be a case similar to Das & Chakrabarti (1999), where they considered little energy loss and found mass outflows in pseudo-Newtonian geometry. However, powerful outflows should carry away a significant amount of ( kinetic) energy.…”

“…That is, mass outflows are not suppressed by relativistic effects and energy dissipation (for a comparison with the psuedo-Newtonian case with no energy dissipation , see, e.g., Das & Chakrabarti [1999]). For a fixed angular momentum, on the other hand, a higher value of fṀ is expected from stronger shocks occurring in the inner regions, and this seems to be the case more in rotating black hole cases (see Fig.…”

“…For instance, mass outflow rate were estimated from adiabatic shocked-flow region in Newtonian gravity (e.g., Chakrabarti 1999;Das 2000). Das & Chakrabarti (1999) took a similar approach to study the shock-generated outflows with little energy dissipation in pseudo-Newtonian geometry. Independently, from general relativistic MHD simulations , the formation of jets (magnetically driven and gas-pressure-driven jets) is found in the high-pressure regions due to the shock/adiabatic compression (e.g., Koide et al 1999;Nishikawa et al 2005).…”

Study of accretion processes around black holes becomes ‘Science’: Tell tale observational signatures of two component advective flows

“…Chakrabarti 2,5,54 presented the first global inflow and outflow solution (GIOS) where a formalism is presented to compute the outflow rate from the inflow rate theoretically. Das and Chakrabarti 60 and Das et al 59 extended this for flows with rotation. It was found that the shock strength is intimately related to the outflow rate.…”

Role of Shocked Accretion Flows in Regulating the Quasi-periodic Oscillation of Galactic Black Hole Candidates

“…This result may have important consequences in connection to the jet formation mechanism for Galactic relativistic sources. It has been shown that (Das 1998;Das & Chakrabarti 1999) the hot and dense postshock region of a BH accretion disk may generate accretion-powered Galactic and extragalactic outflows and that the baryonic load of such outflows increases with the increment of the postshock flow temperature and density. From Figure 2, we conclude that there must be some relationship between the normalized QPO frequencies and the amount of the baryonic content of outflows from Galactic microquasars; the details of such an investigation are reported elsewhere (Das, Rao, & Vadawale 2003).…”